Black Hole polarization betrays galactic centre local magnetic field

Great to see this image

Magnetic swirl: a view of the M87 supermassive black hole in polarized light. The lines mark the orientation of the
polarization, which is related to the magnetic field around the shadow of the black hole. (Courtesy: EHT Collaboration)

in Physics World showing magnetic fied local to the vast Black Hole at the centre of our Galaxy, measured at  230 GHz

We have supplied polarizing grids to a number of the institutions involved in the Event Horizon Telescope (EHT) Collaboration